The present invention relates to a rotary damper, and, in particular, to a rotary damper for damping rotary motion at the end of the stroke.
In some cases of rotary motion, such as when an arm is moving through a vertical arc while carrying a weight, there is a problem with the abrupt stopping of the mechanism at the end of the stroke, which causes an undesirable hammering or jarring of the mechanism. In many cases, the cycling of this rotary motion is very rapid, with cycles in the range of 0.125 to 5 cycles per second, and this hammering at the ends of the stroke can harm the mechanism itself as well as any products that are being carried by the mechanism. Therefore, it would be desirable to have a rotary damper that permits free movement of the mechanism throughout its rotary stroke until the end, where the movement would be damped.
A wide variety of shock absorbers and dampers is known in the art. In the case of rotary dampers, there are dampers which damp the motion along the entire stroke, and there are devices that permit free rotary movement until the end of the stroke, and then provide an abrupt stop at the end of the stroke. Also, it has been known to have a rotary actuator contact mechanical, linear dampers at the ends of its stroke, but this requires multiple mechanisms, which are expensive and which do not work well at high cycle rates. There are not any rotary dampers that permit free rotary movement until the end of the stroke and then provide damping at the end of the stroke.